Well the first thing you need to do is get the pic you want and resize it to 100 pix high. Then you need to upload that pic to a website I used http://www.strikefile.com/myspace/imagehelp.htm or you can use something else. If you use the place I did when you up load the picture you want the DIRECT LINK FOR IMAGE. You then take the url and place it inbetween [img] and [/img]. Then you will be set.
hope this helps
ps just keep trying and testing in the Signutre Testing section of the fourm.